Propiconazole is a fungicide from the triazole group and is a steroid demethylation (ergosterol biosynthesis) inhibitor. It is a systemic foliar fungicide with protective and curative action, with translocation acropetally in the xylem. At labelled application rates, propiconazole controls numerous diseases caused by, for example, Cochliobolus sativus, Erysiphe graminis, Leptosphaeria nodorum, Puccinia spp., Pyrenophora teres, Pyrenophora tritici-repentis, Rhynchosporium secalis and Septoria spp. on cereals; Mycosphaerella musicola and Mycosphaerella fijiensis var. difformis in bananas; Sclerotinia homoeocarpa, Rhizoctonia solani, Puccinia spp., Erysiphe graminis in turf; Rhizoctonia solani, Helminthosporium oryzae and dirty panicle complex in rice; Hemileia vastatrix in coffee; Cercospora spp. in peanuts; Monilinia spp., Podosphaera spp., Sphaerotheca spp. and Tranzschelia spp. in stone fruit; and Helminthosporium spp. in maize. Propiconazole is described in “The Pesticide Manual” [The Pesticide Manual—A World Compendium; Thirteenth Edition; Editor: C. D. S. Tomlin; The British Crop Protection Council] under entry number (675).
Depending on isomeric composition propiconazole is typically a yellowish, odourless, viscous liquid between −10 and 60° C. It is known to crystallise at room temperature over long periods of time. In addition, due to substantial fluctuations in temperature that may occur during processing and storage of agrochemical formulations, propiconazole may go through cycles of melting and recrystallisation leading to the generation of large and undesirable particles. These particles could, for example, block spray nozzles during application of the product. In addition, such melting and recrystallisation events mean that it is difficult to maintain the product as a homogeneous formulation and this may lead to issues during transfer to dilution tanks and in ensuring the correct concentration on dilution. There is thus a need for new forms of propiconazole that will overcome these problems whilst still retaining its advantageous fungicidal properties.